The invention relates to apparatus for manipulating rod-shaped articles, especially rod-shaped articles of the tobacco processing industry. More particularly, the invention relates to improvements in apparatus for rolling rod-shaped articles between moving surfaces so that the articles turn about their respective axes. Such movements of articles are necessary in several types of cigarette making and like machines, for example, to convolute uniting bands around groups of coaxial rod-shaped components to form filter cigarettes of double unit length, to rotate finished filter cigarettes for the purpose of providing their wrappers with perforations for entry of atmospheric air and/or for the purpose of testing the wrappers for the presence of holes, open seams and/or other defects.
It is already known to roll cigarettes and like rod-shaped articles of the tobacco processing industry about their respective axes by advancing the cigarettes in the axially parallel flutes of a rotary drum-shaped conveyor past a cylindrical rolling member which is sufficiently close to the periphery of the conveyor to engage the oncoming cigarettes and to dislodge the engaged cigarettes from their flutes. The cigarettes roll about their respective axes and thus cease to advance with the conveyor, i.e., the conveyor moves relative to the rolling cigarette and advances an oncoming flute into register with such cigarette. The flute communicates with the intake ends of suction ports which enable a suction generating device to attract the freshly rolled cigarette in the adjacent flute. Reference may be had to commonly owned U.S. Pats. Nos. 4,249,545 to Gretz et al. and 4,281,670 to Heitmann et al. which disclose apparatus for making holes in rotating rod-shaped articles by means of one or more beams of coherent radiation, and to commonly owned U.S. Pat. No. 4,277,678 to Wahle et al. which discloses apparatus for optoelectronic testing of the wrappers of rod-shaped articles. The disclosures of these patents are incorporated herein by reference.
A modern cigarette maker turns out very large numbers of articles per unit of time. The apparatus for rotating the articles about their respective axes must be designed with a view to predictably start and terminate the rolling operation and to thus ensure that the articles which have advanced beyond the rolling station are in optimum positions for further treatment, e.g., for transfer onto a different conveyor. This necessitates an abrupt termination of rolling as soon as the articles reach the oncoming flutes because, otherwise, the articles would roll beyond such flutes and could not be properly advanced to the locus of removal from the conveyor and/or to a further processing station. As a rule, presently known apparatus for rolling rod-shaped articles of the tobacco processing industry employ suction generating devices which draw air from the flutes for freshly rolled articles in order to abruptly terminate the rolling step and to maintain the articles in optimum positions for further transport and processing. This necessitates the establishment of a pronounced pressure differential and the provision of a large number of large-diameter suction ports which can lead to deformation of the wrappers and to the generation of pronounced noise.